1. Field of the Invention
The invention generally relates to medical devices and procedures, and more particularly to devices and methods for tissue expansion with fluid delivery and/or drainage.
2. Discussion of Background Information
Breast reconstruction with a tissue expander (TE) is currently the most common technique used for breast reconstruction. Typically immediately after the female has a mastectomy the reconstructive surgeon places a tissue expander which serves to stretch the skin and muscle in order to make room for a future implant or maintain the existing skin envelope. Skin sparing mastectomies are becoming the most common form of breast removal due to cancer, and it is advantageous to salvage this skin envelope. Newer techniques recently developed utilize allograft material, such as treated cadaveric dermis, to shield and hold the tissue expander in the pocket. Problems with the current technique are significant exposure of the patient to potential infection and seroma formation. Seroma is a benign collection of fluid which the body naturally makes following injury or surgery to fill an empty space. This fluid can make the skin turn red over the site where the seroma exists. Studies in plastic and reconstructive surgery have indicated that complications from seroma and/or infection affect 25% of all TE reconstructions.
Typically, when a subject (e.g., patient) develops a seroma, a medical practitioner sticks a large bore needle into the affected area of the subject and extracts the seroma fluid by sucking the fluid out with the needle. Such extraction often requires multiple aspirations. However, this extraction technique (e.g., puncturing with a needle) cannot safely be done with a traditional implanted tissue expander or implant (TE/implant device) because of the risk of puncturing the TE/implant device. If the TE/implant device is punctured, then another surgery would be performed to remove, and possibly exchange, the damaged TE/implant device. Such additional surgery is undesirable if the process that was originally being treated was a benign process, such as a seroma, since the patient would be exposed to undue anesthesia risk and additional infection risk when exchanging the TE/implant.
An infection associated with a TE/implant device also normally causes a reddening of the skin. The patient skin overlying the TE may also become reddened following TE placement and the beginning of placing (e.g., injecting) fluid percutaneously into the TE. Accordingly, a medical practitioner may have a difficult time differentiating between a seroma, an infection, and other common patient reactions. Unfortunately, a surgeon cannot stick a needle into the reddened area for fluid drainage and/or testing because, as already described, this may puncture and deflate the tissue expander if the tissue expander is accidentally stuck with the needle.
Using current methods, a TE that becomes infected must be removed, requiring the patient to undergo another general anesthesia and potentially lose the skin pocket which may have been created with expansion. Although a seroma and an infection have been described thus far as exclusive of one another, these events may be linked. For example, larger seromas often drain through the patient's skin causing an opening and exposing the TE to infection.
A tissue expansion device could also play a role in primary augmentation. Occasionally a primary breast augmentation implant will become infected. The capsule surrounding the TE is relatively avascular and the physician cannot treat infection within such a space. There is no current way to safely place antibiotics percutaneously into the space to fight infection. As such, current treatment involves unwanted additional surgery, such as removing the implant, washing out the pocket and then replacing a new implant over a drain.
More breast reconstructions are being performed with allograft, which has higher incidence of seroma and infection than traditional repair likely due to the fact that the artificial dermis is quite hydrophilic and attracts water around the implant. Also this results in two nonvascular components being next to one another, which increases the likelihood that one or both will become infected.
Thus, a need exists for improved systems and methods that may prevent or treat infections or seroma formations during tissue expansion.